1. Field of the Invention
The present invention relates to a method for driving a field emission device (FED) and a method for aging a field emission display apparatus using the same, and more particularly, to a method for preventing arcing by applying an alternating (AC) voltage as a driving voltage to an FED and improving uniformity of electron emission of a field emission display apparatus comprising a plurality of FEDs.
2. Description of the Related Art
Field emitter array (FEA) type electron emission devices, surface conduction emitter (SCE) type electron emission devices, metal insulator metal (MIM) type electron emission devices, metal insulator semiconductor (MIS) type electron emission devices, and ballistic electron surface emitting (BSE) type electron emission devices use cold cathodes.
Among the electron emission devices, when field emission devices (FEDs), i.e., the FEA type electron emission devices, use a material having a low work function or a high β function as an electron emission source, they employ a principle that electrons are easily emitted in a vacuum state due to a tunneling effect caused by an electric field. The emitter is a tip structure having a sharp leading end made from molybdenum (Mo), silicon (Si), or other similar materials, or a carbon material such as graphite, or diamond like carbon (DLC). Recently, FEDs use nano materials such as nano tubes or nano wires.
The FEA type electron emission devices, i.e., FEDs, are classified as two-electrode structure FEDs and three-electrode structure FEDs according to the arrangement of electrodes.
A two-electrode structure FED is typically constructed with a cathode electrode having an emitter disposed on the upper surface of the cathode electrode, and an anode electrode facing the cathode electrode in order to emit electrons by using an electric potential difference between the cathode electrode and the anode electrode.
A three-electrode structure FED is typically constructed with a gate electrode adjacent to the cathode electrode in order to instigate the emission of electrons. A field emission display apparatus incorporating FEDs includes phosphor material layers on the surface of the anode electrode; the electrons emitted from the emitter are accelerated by the anode electrode to emit light upon impact with the phosphor material.
A contemporary method for driving FEDs applies a driving voltage in the form of a direct current (DC) voltage or a pulse to the electrodes. When the driving voltage is powered on, a voltage drop between the cathode electrode and the anode electrode remains constant, so that a lot of electrostatic particles gather around a tip of the electron emission source, which may cause arcing between the electrostatic particles. In particular, when the driving voltage is either powered off from a power-on state or powered-on from a power-off state, overshoot occurs, which is more likely to cause arcing.
Furthermore, a field emission display apparatus including a plurality of FEDs can easily obtain inconstant light emission such as a hot spot and a dead spot due to a small non-uniform difference between a plurality of tips of the electron emission source. To address this problem, an aging process is performed. The contemporary method for driving FEDs causes a high possibility of arcing during the aging process, and undesirably maintains the hot spot or the dead spot after the aging process is completed.